donpatent
Junior Poster

11 Posts
	
11/05/2004
08:04:51	
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I have been following in the patent literature and the nano related literature, as well, the graphene/graphite sheet electron emitter developments. Some have even suggested that carbon sheets may rival nanotubes.

Matsushita:
(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) 
(11) WO 2004/095494 
(13) A1 
(21) PCT/JP2004/005703 
(22) 21 April 2004 (21.04.2004) 
(25) Japanese 
(26) Japanese 
(30) 2003-116841 22 April 2003 
(22.04.2003) JP 
(43) 04 November 2004 (04.11.2004) [published]
(51)7 H01J 1/304 , 9/02 , 31/12 , 29/04 
(54) ELECTRON-EMITTING MATERIAL, ITS PRODUCING METHOD, ELECTRON-EMITTING DEVICE USING SAME, AND IMAGE DRAWING DEVICE
(71) MATSUSHITA ELECTRIC INDUSTRIAL CO. LTD. [JP/JP]; 1006, Oaza Kadoma, Kadoma-shi, Osaka, 5718501 (JP).

Abstract
(57) An electron-emitting material having a field-emission start voltage or work function smaller than conventional ones. The material comprises a substrate (102) and a graphite sheet (101) laminated on the substrate (102). (1) The graphite sheet (101) has a structure in which graphenes each composed of a carbon hexagonal network surface are layered, (2) the graphemes are so stacked that the c-axis direction of each grapheme is substantially perpendicular to the surface of the substrate (102), (3) the graphite sheets (101) is so laminated on the substrate (102) that the c-axis direction of each grapheme is substantially perpendicular to the surface of the substrate (102), and (4) the graphite sheet (101) each contains an element other than carbon as a second element. 

NEC
United States Patent Application 20040217382 
Kind Code A1 
Konuma, Kazuo November 4, 2004 

Electron emission film and electric field electron emission device 

Abstract
An electron emission film capable of enhancing or suppressing electron emitting characteristics at part of an electron emitting surface, and an electric field electron emission device. Many single-wall carbon nanotubes each having a slender crystal structure are arranged at the center of a CNT film (13) in such a posture as to project almost vertically with respect to the film surface. That is, a fiber structure at a specific surface (raised surface (14)) is oriented vertically to promote electron emission, or a fiber structure is made flat by an action of surface tension to suppress electron emission from a specific surface. For example, the edge portion of a CNT film, which is an area from which electrons are emitted curvedly, is rendered a flat-hair surface (15). 

Inventors: Konuma, Kazuo; (Tokyo, JP)[This inventor, from the issued patents in his name is an NEC employee]

From the specification:
[0076]....The reference numeral 61 designates a graphite emission film.

[0221] [Eleventh Embodiment] 

[0222] A description will be made of the eleventh embodiment of the present invention. This embodiment is concerned with the electron emission film of a graphite film (not shown). The graphite film does not have minute projections but has exposed potions where a work function is small in places on its surface. That is, the graphite film is a film on which areas where a work function is small are scattered. 

[0223] The graphite films are deposited in stripes on a glass substrate, and the edge part thereof is covered by nickel metal. As a result, electron emission from the edge part is suppressed, and electrons are emitted from only the central portion of the surface. 

[0235] A description will be made of the thirteenth embodiment of the present invention. FIG. 21 is a cross sectional view showing the configuration of an FED using a graphite emission film according to the thirteenth embodiment of the present invention. In the FED 60 of this embodiment, a graphite emission film 61 is deposited on a 1 .mu.m-thick iron wiring 62 formed on a glass substrate by CDV (Chemical Vapor Deposition). The thickness of the formed film is 1 .mu.m thick. 

[0239] In the FED shown in FIG. 21, an insulating film 68 and a gate electrode 65 are formed around the graphite emission film 61 so as to form an emitter hole 67. The effective portion of insulating film corresponding to the emitter hole is 5 .mu.m, and the gate electrode is 8 .mu.m in thickness. The emitter hole 67 has a diameter of 50 .mu.m. The aluminum center cover 63 is located in the center of the emitter hole 67. 

As well, I have seen involvement by Canon, Nano-Proprietary, and various university researchers - Manchester University (Geim), Georgia Tech (Phillip First), National University of Singapore/NUS (Yihong Wu). 

Nano-Proprietary issued a PR about their involvement:
http://biz.yahoo.com/pz/040826/62959.html

I have all this graphitic carbon sheet/wall/flake emitter development documented here for easy reference:
http://www.geocities.com/mr_module/NanoWall-NanoFlake.html

It is my considered opinion that NNPP in view of the shortly to be issued US patent with its very early priority date of August 21, 2000 will DOMINATE this rather important new development in much the same way, if not more so, than it dominates the use of CNTs in FEDs.

Edited by - donpatent on 11/22/2004 13:34:46 	
donpatent
Junior Poster

11 Posts
	
11/17/2004
17:22:06	

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The NNPP "shortly to be issued US patent" has issued as:

US patent 6,819,034, Nov. 16, 2004
CARBON FLAKE COLD CATHODE
U.S. application number 09/642,955
Priority date August 21, 2000

Claim: 
1. An apparatus comprising: 
a substrate; 
a film of carbon flakes deposited on the substrate.

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=6,819,034.WKU.&OS=PN/6,819,034&RS=PN/6,819,034

The patent specifies the advancements:
Carbon flake field emitters differ from the other carbon-based cold cathodes in the following: 

1. Better electric conductivity since the carbon flakes have a graphitic structure. As well as in graphite, the conductivity along the basal plane of the flake is almost metallic. 

2. More robust than nanofibers since they are a two-dimensional structure rather than one-dimensional like the materials from the second category. 

3. An increasingly extended emission area over the flake edge that enables higher emission currents. 

4. Less susceptible to spoiling the field enhancement factor since this factor is a square root function of a length-to-thickness ratio for edge emission unlike a linear function of this ratio for tip emission from carbon fibers and nanotubes. 

	

Edited by - donpatent on 11/17/2004 17:36:31